The biological effects of chemical contaminants in the Arabian/Persian Gulf: A review

© 2019 Elsevier B.V. The Arabian Gulf is a shallow sea naturally exposed to extreme conditions of temperature and salinity due to its location, semi-enclosed nature, bathymetry and restricted circulation. Compared to open marine systems, the added stress imposed by pollutants is likely to have additional adverse consequences. Maintaining good marine environmental quality is crucial for several socio-economic reasons, one of the most important being that the region relies heavily on seawater as a source of freshwater through desalination. While regionally based marine monitoring programs employing chemical endpoints have been widely deployed, few have evaluated the potential biological effects of those contaminants detected. However, it is now widely recognized that an integrated approach using both chemical measurements and appropriate biological endpoints in key sentinel species is essential to the design and implementation of marine environmental programs. Here we present an exhaustive review of the studies published so far in the Gulf on the biological effects of chemical contaminants using different biological endpoints and suggest potential areas requiring additional research.This publication was made possible by the NPRP award [NPRP9-394-1-090 “The Pearl Oyster: from national icon to guardian of Qatar’s marine environment”] from the Qatar National Research Fund (a member of Qatar Foundation). The findings herein reflect the work, and are solely the responsibility, of the authors

De novo transcriptome assembly of the Qatari pearl oyster Pinctada imbricata radiata

© 2019 The pearl oyster Pinctada imbricata radiata is an iconic species in Qatar, representing an integral part of the nation's cultural heritage and one of the main economic foundations upon which the nation developed. During the early part of the 20th century, nearly half the Qatar population was involved in the pearl oyster industry. However, the fishery has undergone steady decline since the 1930s, and the species is now under threat due to multiple confounding pressures. This manuscript presents the first de novo transcriptome of the Qatari pearl oyster assembled into 30,739 non-redundant coding sequences and with a BUSCO completeness score of 98.4%. Analysis of the transcriptome reveals the close evolutionary distance to the conspecific animal Pinctada imbricata fucata but also highlights differences in immune genes and the presence of distinctive transposon families, suggesting recent adaptive divergence. This data is made available for all to utilise in future studies on the species.This publication was made possible by the NPRP award [NPRP9-394-1-090 “The Pearl Oyster: from national icon to guardian of Qatar's marine environment”] from the Qatar National Research Fund (a member of Qatar Foundation). The findings herein reflect the work, and are solely the responsibility, of the authors. In addition, the authors would like to thank Prof. Eduarda Santos for advice regarding sequencing requirements and Mr. Mark Chatting and Mr. Reyniel Gasang for their support in the collection of the samples

Enhancing the Quality of "Produced Water" by Activated Carbon

The main objective is to contribute via this study, in solving an environmental issue and helping Qatar in finding suitable water resources; useful in agriculture. Qatar faces diverse water challenges; the number one that threats here is scarcity as water is not renewable. Due to scarcity of good quality water, reusing of low quality and contaminated water is highly increasing in Qatar. The main source of water in Qatar is desalination stations. Most of the desalinated water is for human usage. Agriculture in Qatar depends mainly on underground water; it is available but always saline and found in insufficient quantities. Due to the increasing demand for water among industries and irrigation, using other alternative water resources such as produced water during oil and gas extraction would be of importance. Generally, produced water is the water that exists in subsurface and is moved to the surface through oil and gas processes. The volume of produced water and pollutants concentration vary depending on the nature and location of the oil products. It represents the major waste stream related to oil and gas processes. Large volume of produced water generated in Qatar has the potential to enhance the water resources. The crucial goal of produced water management is to eliminate dissolved harmful components and use it for beneficial uses that can efficiently improve environmental impact and water shortage. An exclusive characteristic of produced water comparing to other wastewater resources is the large variation and complexity in water chemistry. This would play a vital role in the remediation processes.qscienc

Ecogenotoxicological Impact of Marine Pollutants on Qatari Bivalves: An Experimental Approach

The geographical and hydrological characteristics and industrial activities of the Arabian/Persian Gulf contribute to its classification as a stressed marine environment. The persistency of some contaminants released by human activity is putting additional pressure on this already fragile system. Several studies have assessed the chemical contamination levels in Qatari coastal sediments but this is one of a few studies that assessed their eco-genotoxicological impacts, by using cytogenetic endpoints in a local model bivalve species. Bivalves were specifically selected for this study due to their role as filter feeders, high tolerance for harsh environmental conditions, and availability around Qatar. In this project, determination of Polycyclic Aromatic Hydrocarbons (PAHs), Total Petroleum Hydrocarbons (TPHs) and trace metals in surface sediments and pearl oyster -Pinctada radiata- was conducted in samples collected from 3 coastal locations in Qatar: Umm Bab, Dukhan and Al-Wakra. The selected sites were expected to be dissimilar in regard to the chemical pollutant level and contaminants distribution due to the different anthropogenic activities. Initial aneuploidy levels –numerical abnormality in chromosomes- in oysters were examined between December 2015 to February 2016 through randomly selecting 140 well spread metaphases. Metaphases with 26 chromosomes were recorded as diploid or normal and the ones with less or more number of chromosomes considered aneuploidy (Ebied, 1999). The ability of the oysters to adapt in terms of chemical contaminants accumulation and aneuploidy level when moved between sites with different levels of chemical pollution was assessed in the second sampling in April 2016, and using experimental approach with three treatments (control, transplanted, and translocated). The control treatments were collected from the original site and kept there, the transplanted treatments consisted of individuals composed from the other two sites and moved to Al-Wakra and the opposite, while the translocated treatment were the ones moved from Dukhan to Umm Bab and versa vise. Statistical analysis showed significant difference between sediment in the three sites; TPHs concentrated in Umm Bab, higher concentrations of metals found in Dukhan, while PAHs concentrated the most in AL-Wakra. Hydrocarbons and metals were detected in higher doses in oyster tissues collected in first sampling comparing to those analyzed in the second sampling with consistency of accumulating same contaminants. Predation by gastropod whelks caused high mortality of oyster during the second stage of the study especially in Dukhan control while transplanted animals from Al-Wakra were the least selected by gastropods. Mortality rates in Dukhan were generally higher than in other sites, except for oysters transplanted from Al-Wakra to Dukhan. Positive correlation was found between the high levels of contaminants and aneuploidy during the first phase. Unexpectedly, to the usually observed in bivalves, there was a bigger percentage of abnormal cells with chromosomal gain (hyperdiploids) than with chromosomal loss (hypodiploids) in all treatments. Among all the treatments, transplanted oysters showed the lowest level of aneuploidy followed by translocated, then control. In other words: oysters moved from site to another, regardless of the contamination levels at origin and destination, showed some recovery from initial aneuploidy levels. Further research is needed to determine the underlying mechanisms for this pattern.qscienc

Is it forever? Genotoxicological impact of marine contaminants on Arabian/Persian Gulf bivalves: An experimental approach

© 2020 Elsevier B.V. A novel approach of combining manipulative field experiments and cytogenetic endpoints was used to assess the genotoxic impact of chemical contamination on a local model bivalve species, the pearl oyster -Pinctada imbricata radiata. Baseline levels of Polycyclic Aromatic Hydrocarbons (PAHs), Total Petroleum Hydrocarbons (TPHs) and trace metals were determined from surface sediments and pearl oyster tissue collected from 3 coastal locations in Qatar (Umm Bab, Dukhan and Al-Wakra). Initial aneuploidy –numerical chromosomal abnormality-level in oysters was also assessed during the baseline survey. The oysters’ ability to adapt to new sites, with distinct signatures in terms of chemical contamination, was assessed using a reciprocal transplantation experiment among the same 3 coastal locations, from February to April 2016. Significant differences in sediment contamination levels were detected among the 3 sites. TPHs were in higher concentrations at Umm Bab (western coast), while higher concentrations of metals and PAHs were found at Dukhan (western coast) and Al-Wakra (eastern coast), respectively. Oysters transplanted between locations showed lower levels of aneuploidy, relative to those kept in the original location (controls). Transplanted oysters, regardless of the contamination levels at the origin and destination, showed recovery from initial aneuploidy levels. Moreover, there was a larger percentage of aneuploid cells with chromosomal gain than with chromosomal loss in all treatments, which contrasts with the pattern usually observed in bivalves.This work was supported by Qatar University [grant QUSTCAS-FALL-15/16-32]. The authors are thankful to the QU-DBES staff: Mariam Safi, DM Estremadura, Khwaja Abdul Matheen, Abdol Ali Moghaddasi and Muhammad Habeeb. Also thanks to the QU-ESC staff: Noora Al Shamary, Hassan Hassan, Mazen Assali, Sara Al Saadi, Mariem Bastaki and Hamood Al Saadi. The authors are also grateful to Ismail Al-Shaik and Linso Varghese from Exxon Mobil for helping with the inorganic analysis and to Dr. Elizabeth Goergen, for proofreading the manuscript

Pearl Oyster: from national icon to guardian of Qatar's marine environment

The NPRP9-394-1-090 project "Pearl Oyster: from national icon to guardian of Qatar's marine environment" had as main aim to develop and apply an integrated suite of chemical and biological methods as early warning tools to assess the "health" of Qatar's marine environment. The central theme consisted in an investigative monitoring program around the use of the pearl oyster, Pictada imbricata radiata, as a sentinel or guardian species. We have characterized the main environmental contaminants of concern at a selected number of sites around the Qatari coast (UmmBab, Al Khor, Al Wakra and Simaisma), during 2 years, in summer and winter. Potential ecological effects of contaminants (targeted and untargeted) were investigated at different biological organization levels (gene, chromosome, cell, individual, population), through a multidisciplinary approach, using classical and genotoxicological endpoints, integrative histopathology and transcriptomic responses to the different environmental stresses. To our knowledge, this is the first time an integrated approach connecting all these disciplines has been applied in the Qatari marine environment. We present here the main results, of this 3 years project, obtained in all different disciplinary approaches. The results of this project will leave a legacy of resources for future Qatari researchers, including an open access transcriptome data base and the first description of common pathologies observed in the pearl oyster P. i. radiata. Moreover, they will also represent a sound science-based baseline data essential for conservation and management planning, by integration of the data from all the different disciplines applied in the project to assess the potential ecological effects of contaminants at different biological levels